A vacuum microwave drying and cracking device

Abstract

The utility model discloses a vacuum microwave drying and cracking device, comprising a preheating mechanism: comprising a preheating chamber, which is used for preheating materials to be dried; a microwave drying and cracking mechanism: which is used for performing microwave drying and cracking on the preheated materials; a negative pressure mechanism: which is used for evacuating the preheating chamber and a microwave drying and cracking box to obtain a negative pressure environment, and the negative pressure mechanism is connected with the preheating mechanism; the microwave cracking and drying device of the utility model adopts the application of a two-stage integrated double-helix microwave device, and the heating efficiency is more than doubled than that of a traditional heating device, which greatly improves the problems of energy non-concentration, low efficiency and unevenness commonly existing in industrial microwave heating, reduces unnecessary energy consumption and waste, improves energy utilization, shortens heating time, prolongs its service life, reduces production cost, and is of great significance for large-scale industrial applications.

Description

Technical Field

[0001] The utility model relates to the technical field of material drying, in particular to a vacuum microwave drying and cracking device. Background Art

[0002] Granulated blast furnace material powder (referred to as material powder) refers to a powder product obtained by ultra-fine grinding of water-quenched materials discharged from iron-making blast furnaces. It can improve the durability and workability of concrete and is a mineral fine admixture with excellent performance. The raw materials of material powder have a high water content, generally 10-12%, and the water exists in the form of free water and bound water. If the raw materials with high water content are directly put into the grinding equipment, on the one hand, it is easy to cause a large amount of free water to be retained in the grinding equipment, causing the equipment to rust and corrode, reducing the service life of the grinding equipment and causing economic losses; on the other hand, the raw materials with high water content directly entering the grinding equipment cause the grinding time and drying time of the materials to be prolonged. In addition, in the actual production process, due to the high water content of the material, it is very easy to cause compaction and blockage of the equipment during the material transmission process, affecting the normal production efficiency.

[0003] Due to the high moisture content of raw materials, the material micro powder production line is generally equipped with a hot air furnace system that uses the heat generated by the combustion of coal powder, coal gas or natural gas to dry the raw materials. However, the exhaust gas from drying the raw materials using such a hot air furnace system contains a variety of complex environmental pollutants, such as dust, SOX, NOx, CO2, HF, VOC, PAHs, dioxins and other pollutants and toxic gases. These exhaust gases are discharged into the atmosphere through the chimney, causing environmental pollution. Moreover, the waste heat generated during the drying process of the material micro powder production line is not fully and reasonably utilized. Only part of the waste heat is recycled, and the rest is discharged into the atmosphere through the chimney, wasting energy.

[0004] As a rapidly developing new energy source, microwaves have the characteristics of non-conductive heating, fast heating speed, uniform heating, selective "body" heating, no thermal inertia, high heat transfer efficiency, convenient control, and high degree of automation. Compared with existing heating furnaces, steam, and waste heat drying, it embodies many advantages such as high efficiency, energy saving, and environmental protection. The development of microwave heating technology provides a strong technical guarantee for enterprises to achieve the goal of "energy saving and emission reduction", update production processes, and improve equipment levels. However, there are also problems in microwave heating technology that cannot be ignored. First, after the equipment is processed and formed, the microwave device is fixed at a certain position. The "hot spot" problem caused by the uneven distribution of the electromagnetic field makes the microwave heating uneven. In severe cases, the local temperature may be too high, burning the microwave reactor, causing major safety accidents, affecting the application of microwave heating in industry. At present, the microwave heating device used in industry generally heats materials in a stationary state relative to the microwave source or moves in a single direction. In this way, due to the uneven distribution of the electromagnetic field intensity in the heating device, the temperature distribution of the drying and heating materials will be uneven. Therefore, comprehensive consideration of the integrated design of industrial microwave drying equipment not only dries the materials quickly but also improves the heating efficiency, which has become the biggest challenge in the current industrial application of microwave energy.

[0005] At present, my country's existing slag micropowder production capacity ranks first in the world. Focusing on the existing material micropowder production process and combining it with new microwave heating technology, the uniformity and efficiency of microwave heating can be improved, the quality of material micropowder can be guaranteed, and the production operation can be stable. Increasing economic benefits is an effective way to adapt to the development of the country and enterprises and to improve the economic and social benefits of enterprises. Summary of the invention

[0006] The purpose of the utility model is to provide a vacuum microwave drying and cracking device, which can not only realize large-scale continuous production of materials, but also has microwave drying and cracking functions. It has a simple structure, scientific and reasonable design and easy operation. It can realize heat microcirculation of materials in the spiral stirring and conveying, and realize rapid drying and cracking of materials by constructing a microwave mechanical force composite field, so as to achieve the purpose of homogenizing and drying the materials. It has high drying and cracking efficiency, low energy consumption, small system investment and high economic benefits. More importantly, it can avoid the emission of pollutants from the heating and combustion furnace and achieve the goal of "energy saving, emission reduction and carbon reduction".

[0007] In order to achieve the above-mentioned purpose, the utility model provides a vacuum microwave drying and cracking device, comprising:

[0008] Preheating mechanism: comprising a preheating bin, used for preheating the material to be dried, the preheating bin is provided with a feed inlet, and the feed inlet is connected to the discharge port of the material storage bin to be dried;

[0009] Microwave drying and cracking mechanism: used for performing microwave drying and cracking on the preheated material, comprising a microwave drying and cracking box and at least one microwave device fixedly arranged on the microwave drying and cracking box, wherein the feed inlet of the microwave drying and cracking box is connected to the discharge outlet of the preheating bin through a connecting pipe;

[0010] Negative pressure mechanism: used for evacuating the preheating chamber and the microwave drying and cracking box to obtain a negative pressure environment, and the negative pressure mechanism is connected to the preheating mechanism.

[0011] The utility model proposes a two-stage double-helix vacuum microwave drying and cracking device, which can realize double microcirculation of microwave energy and heat energy in the two-stage double-helix device. The material moves in the horizontal direction and the vertical direction at the same time under the action of the double-helix propeller, so that the electromagnetic energy and heat energy absorbed by the material tend to be uniform over time, thereby improving the heating efficiency and energy utilization rate, and can quickly dry and crack the material to achieve "energy saving and emission reduction". At the same time, the material is a mixture of multiple substances. The microwave has good penetrating ability and can quickly enter the interior of the molecule to generate a large amount of heat, causing the material to be heated and expand and break the wall, making the material mixture more loose and porous and cracks appear between the particles, greatly improving its grindability and grinding efficiency, making the material easier to grind and grind. Compared with traditional heating, it can obviously reduce the grinding cost and improve the output and quality of material micro powder.

[0012] Preferably, a first double-screw feeder is fixedly provided in the preheating chamber, and a first motor for driving the first double-screw feeder is provided on the preheating chamber. A double-screw feeder is added to the two-stage integrated double-screw microwave device, so that when microwaves heat materials and absorbing materials, the rotation of the screw propeller will drive the heated materials to rotate and advance at the same time, so that the position of the materials will change in the axial and radial directions at the same time, that is, it will move in the horizontal and vertical directions at the same time. The position of the materials changes with time in both the horizontal and vertical directions, and will not always be in a position where the electromagnetic field is very strong or very weak. The movement of the materials effectively overcomes the problem of uneven distribution of the microwave magnetic field in the double helix, greatly improving the efficiency of microwaves, and the absorbed electromagnetic field energy and heat energy will be more uniform, thereby improving the temperature uniformity of the materials in the device, and realizing the optimized design of a microwave heating device with uniform microwaves and high efficiency.

[0013] Preferably, a second double-screw feeder is fixedly arranged in the microwave drying and cracking box, and a second motor for driving the second double-screw feeder is arranged on the microwave drying and cracking box. Compared with the single-screw conveyor, the double-screw conveyor has a stirring function and is not easy to be blocked; at the same speed, because the helix angle of the double-screw blade is higher than that of the single-screw blade, the blade conveying flow rate per unit time is larger, and its conveying capacity has increased to 1.5-2 times of the original single-screw, meeting the requirements of large industrial production lines with an annual output of 600,000 tons to 1.5 million tons of material micro-powder.

[0014] Preferably, the negative pressure mechanism includes a vacuum pump, a vacuum tank and a water storage tank, the vacuum pump is connected to the vacuum tank through a vacuum pipe, the vacuum tank is connected to the water storage tank, and the vacuum tank is connected to the preheating chamber. The negative pressure mechanism can be automatically recycled according to the temperature, humidity, pressure data and the vacuum negative pressure value, and automatically performs vacuum negative pressure air extraction. The utility model adopts a vacuum negative pressure microwave drying and cracking device to dry materials, making full use of the fact that the propagation speed of microwaves in a vacuum is greater than that of air, thereby improving the microwave radiation efficiency. In addition, the utility model does not require the consumption of fossil energy, does not produce harmful gases, and is green, clean, and environmentally friendly.

[0015] Preferably, the microwave device is a radiation type microwave heater, and the radiation type microwave heater is fixedly arranged on the top cover plate of the microwave drying and cracking box. The utility model adopts microwaves to provide a heat source, does not consume fossil energy, does not produce harmful gases, and is green, clean and environmentally friendly. Since microwave drying technology does not require heat conduction, heat can be generated from the inside of the bulk material, and the moisture inside and outside the bulk material is heated at the same time. The temperature of the bulk material is low outside and high inside. After the moisture is heated and vaporized, a huge pressure difference is generated, and the driving force formed causes the moisture to be quickly transferred from the inside of the material to the outside.

[0016] Preferably, the connecting pipe is made of stainless steel, and a foam insulation layer is fixedly arranged on the side wall of the connecting pipe. The foam insulation layer can ensure the temperature of the medium and the temperature of the connecting pipe.

[0017] Preferably, the inner wall of the microwave drying and cracking box is provided with a wave-absorbing composite material layer and a non-wave-absorbing thermal insulation layer from the inside to the outside. At the same time, the wave-absorbing composite material layer on the inner surface of the box absorbs microwaves not absorbed by the material, and converts microwave energy into heat energy for indirect heating of the material particles, and the non-wave-absorbing thermal insulation layer in the stainless steel box does not absorb waves and maintains the temperature in the box of the two-stage double-helix microwave device.

[0018] Preferably, the composition of the absorbing composite material layer is selected from at least one of iron-based absorbing materials and carbon-based absorbing materials; the composition of the non-absorbing thermal insulation layer is selected from at least one of rock wool board, foam cement board and glass wool board.

[0019] Preferably, the microwave drying and cracking box is provided with a humidity detection device and a temperature and pressure detection device, and the operation of each mechanism is adjusted at any time according to the temperature, humidity and pressure in the material storage tank detected by the humidity detection device and the temperature and pressure detection device.

[0020] Preferably, a material pouring valve is connected to the bottom of the microwave drying and cracking box.

[0021] In summary, the application of the two-stage integrated double-helix microwave device in the microwave cracking and drying device of the utility model has a heating efficiency more than doubled that of the traditional heating device, which greatly improves the energy concentration, low efficiency and unevenness commonly existing in industrial microwave heating, reduces unnecessary energy consumption and waste, improves energy utilization, shortens heating time, extends its service life, and reduces production costs, which is of great significance for large-scale industrial applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the structure of the vacuum microwave drying and cracking device of the utility model.

[0023] In the figure:

[0024] 1. Preheating mechanism; 11. Preheating chamber; 12. First double-screw feeder; 13. First motor; 2. Microwave drying and cracking mechanism; 21. Microwave drying and cracking box; 22. Radiation type microwave heater; 23. Second double-screw feeder; 24. Second motor; 3. Connecting pipeline; 4. Negative pressure mechanism; 41. Vacuum pump; 42. Vacuum tank; 43. Water storage tank; 5. Humidity detection device; 6. Temperature and pressure detection device; 7. Storage bin for materials to be dried; 8. Dumping valve. DETAILED DESCRIPTION

[0025] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and understandable, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0026] like Figure 1 As shown, the utility model provides a vacuum microwave drying and cracking device, comprising:

[0027] Preheating mechanism 1: comprising a preheating bin 11, used for preheating the material to be dried, the preheating bin 11 is provided with a feed port, the feed port is connected to the discharge port of the material storage bin 7 to be dried, a first double-screw feeder 12 is fixedly provided in the preheating bin 11, and a first motor 13 for driving the first double-screw feeder 12 is provided on the preheating bin 11;

[0028] The microwave drying and cracking mechanism 2 is used to perform microwave drying and cracking on the preheated material, comprising a microwave drying and cracking box 21 and at least one radiation type microwave heater 22 fixedly arranged on the microwave drying and cracking box 21, the radiation type microwave heater 22 is fixedly arranged on the top cover plate of the microwave drying and cracking box 21, the feed inlet of the microwave drying and cracking box 21 is connected to the discharge port of the preheating bin 11 through the connecting pipe 3, a second double screw feeder 23 is fixedly arranged in the microwave drying and cracking box 21, and a second motor 24 for driving the second double screw feeder 23 to move is arranged on the microwave drying and cracking box 21;

[0029] Negative pressure mechanism 4: used to evacuate the preheating chamber 11 and the microwave drying and cracking box 21 to obtain a negative pressure environment. The negative pressure mechanism 4 is connected to the preheating mechanism 1. The negative pressure mechanism 4 includes a vacuum pump 41, a vacuum tank 42 and a water storage tank 43. The vacuum pump 41 is connected to the vacuum tank 42 through a vacuum pipe. The vacuum tank 42 is connected to the water storage tank 43. The vacuum tank 42 is connected to the preheating chamber 11.

[0030] The utility model proposes a two-stage double-helix vacuum microwave drying and cracking device, which can realize double microcirculation of microwave energy and heat energy in the two-stage double-helix device. The material moves in the horizontal direction and the vertical direction at the same time under the action of the double-helix propeller, so that the electromagnetic energy and heat energy absorbed by the material tend to be uniform over time, thereby improving the heating efficiency and energy utilization rate, and can quickly dry and crack the material to achieve "energy saving and emission reduction". At the same time, the material is a mixture of multiple substances. The microwave has good penetrating ability and can quickly enter the interior of the molecule to generate a large amount of heat, causing the material to be heated and expand and break the wall, making the material mixture more loose and porous and cracks appear between the particles, greatly improving its grindability and grinding efficiency, making the material easier to grind and grind. Compared with traditional heating, it can obviously reduce the grinding cost and improve the output and quality of material micro powder.

[0031] A double-helix feeder is added to the two-stage integrated double-helix microwave device, so that when the microwave heats the material and the absorbing material, the rotation of the spiral propeller will drive the heated material to rotate and advance at the same time, so that the position of the material will change in the axial and radial directions at the same time, that is, it will move in the horizontal and vertical directions at the same time. The position of the material changes with time in the horizontal and vertical directions and will not always be in a position where the electromagnetic field is very strong or very weak. The movement of the material effectively overcomes the problem of uneven distribution of the microwave magnetic field in the double helix, greatly improving the efficiency of the microwave, and the absorbed electromagnetic field energy and heat energy will be more uniform, thereby improving the temperature uniformity of the material in the device, and realizing the optimized design of a microwave heating device with uniform microwave and high efficiency.

[0032] The negative pressure mechanism 4 can be automatically recycled according to the temperature, humidity, pressure data and vacuum negative pressure value, and automatically perform vacuum negative pressure air extraction. The utility model adopts a vacuum negative pressure microwave drying and cracking device to dry materials, making full use of the fact that the microwave propagation speed in a vacuum is greater than that in air, thereby improving the microwave radiation efficiency. In addition, the utility model does not need to consume fossil energy, does not produce harmful gases, and is green, clean and environmentally friendly.

[0033] The utility model adopts microwaves as heat source, does not consume fossil energy, does not produce harmful gases, and is green, clean and environmentally friendly. Since microwave drying technology does not require heat conduction, heat can be generated from the inside of bulk materials, and the moisture inside and outside the bulk materials is heated at the same time. The temperature of the bulk materials is low outside and high inside. After the moisture is heated and vaporized, a huge pressure difference is generated, and the driving force formed causes the moisture to be quickly transferred from the inside of the material to the outside.

[0034] In this embodiment, the connecting pipe 3 is made of stainless steel, and a foam insulation layer is fixedly arranged on the side wall of the connecting pipe 3. The foam insulation layer can ensure the temperature of the medium and the temperature of the connecting pipe 3.

[0035] In this embodiment, the inner wall of the microwave drying and cracking box 21 is provided with a wave-absorbing composite material layer and a non-wave-absorbing thermal insulation layer from the inside to the outside. At the same time, the wave-absorbing composite material layer on the inner surface of the box absorbs microwaves not absorbed by the material, and converts microwave energy into heat energy for indirect heating of the material particles. The non-wave-absorbing thermal insulation layer in the stainless steel box does not absorb waves and maintains the temperature in the box of the two-stage double-helix microwave device.

[0036] Furthermore, the composition of the absorbing composite material layer is selected from at least one of iron-based absorbing materials and carbon-based absorbing materials; the composition of the non-absorbing thermal insulation layer is selected from at least one of rock wool board, foam cement board and glass wool board.

[0037] In this embodiment, the microwave drying and cracking box 21 is provided with a humidity detection device 5 and a temperature and pressure detection device 6. The operation of each mechanism is adjusted at any time according to the temperature, humidity and pressure in the material storage tank detected by the humidity detection device 5 and the temperature and pressure detection device 6.

[0038] In this embodiment, a material pouring valve 8 is connected to the bottom of the microwave drying and cracking box 21 .

[0039] In this embodiment, the preheating chamber 11 and the microwave drying and cracking box 21 adopt an integrated design of material transportation, microwave heating, and microwave-absorbing composite materials. The uniformly distributed microwave field generated by the microwave source and the heat energy generated by the microwave-absorbing composite materials double-dry and crack the materials transported in a double-screw manner, thereby improving the uniformity and efficiency of microwave heating. The sealing of the materials at both ends avoids the leakage of microwaves to the outside.

[0040] In this embodiment, the preheating chamber 11 and the microwave drying and cracking box are set up with a certain inclination. In other embodiments, they can be adjusted upward or downward according to the material characteristics and on-site conditions, or they can be horizontal.

[0041] It is worth mentioning that the pipe radius of the preheating chamber 11 and the microwave drying and cracking box 21 is calculated according to the conveying volume to determine the optimal pipe radius to achieve uniform heating.

[0042] In other embodiments, the microwave drying and cracking box 21 dries the cracked and transported materials, and a microwave source with a constant output power may be used to control the microwave energy received by the material by adjusting the microwave irradiation time of the material. A microwave source with adjustable output power may also be used to control the microwave energy received by irradiating the material with microwaves for a fixed time.

[0043] In other embodiments, the number of the radiation type microwave heaters 22 can be adjusted according to the transport volume and moisture content of the material, and the final moisture content of the material can be controlled by the number of the radiation type microwave heaters 22 and the speed of the double helix.

[0044] In other embodiments, an intelligent expert control system for microwave drying cracking materials is also included. Through the moisture content, particle size, flow rate, temperature parameters, comprehensive energy utilization, etc. before and after entering the mill, the software for online analysis and predictive analysis of the microwave drying cracking material processing process production is used to dynamically balance the energy of the material micro powder production system and improve the comprehensive energy utilization efficiency.

[0045] The use method and principle of the vacuum microwave drying and cracking device of the utility model are as follows:

[0046] S1, provide materials to enter the storage silo;

[0047] S2, the first double screw feeder 12 in the preheating chamber 11 adopts frequency conversion conveying, and automatically controls the material conveying amount according to a given value. The hot steam generated by the microwave drying and cracking box 21 enters the preheating chamber 11 through the connecting pipe. After the hot steam preheats the material, the material enters the microwave drying and cracking box 21 through the connecting pipe 3, and the material conveying is reverse to the steam airflow;

[0048] S3, turn on the second double screw feeder 23 in the microwave drying and cracking box 21 to convey the material, use frequency conversion to convey, and match the material conveying amount of the first double screw feeder 12, the radiation type microwave heater 22 generates microwaves to form a uniformly distributed microwave field, which is transmitted to the material without loss, and at the same time, the absorbing composite material on the inner surface of the box absorbs the microwaves not absorbed by the material, and converts the microwave energy into heat energy for indirect heating of the material particles, and controls the temperature rise range below 300 degrees through temperature detection to dry the cracking material;

[0049] S4. The moisture content of the material particles is stabilized at the set value through the detection and control device, and then the hot material is directly sent into the material conveying system through the transition pipe;

[0050] S5. The upper and lower limits set by the negative pressure mechanism 4 are automatically circulated to perform vacuum negative pressure air extraction; first, the vacuum in the microwave drying and cracking box 21 is extracted to form a negative pressure environment in the box, and then the radiation type microwave heater 22 is started. The hot steam generated enters the preheating chamber 11 through the connecting pipe 3, and the residual heat is discharged through the vacuum pump 41, and then condensed, collected and sent to the water collecting tank.

[0051] In other ways of use, through theoretical analysis of materials, laboratory research and simulation experiments, in the study of heat transfer, mass transfer and dielectric properties in the microwave field, an expert mathematical model is established, and fully automated control with a human-machine interface is adopted to achieve precise and optimal control of material drying and cracking.

[0052] Compared with the existing heating furnace technology, the microwave drying and cracking device of the utility model completely avoids the environmental pollution caused by pollutants and toxic gases such as dust, SOX, NOx, CO2, VOC, PAHs, dioxins in the exhaust gas generated by the hot air furnace system for drying raw materials, thereby achieving the goal of "energy saving and emission reduction".

[0053] Although the utility model is disclosed as above, the protection scope of the utility model is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the disclosure, and these changes and modifications will fall within the protection scope of the utility model.

Claims

1. A vacuum microwave drying cracking device, characterized in that: include, The preheating mechanism (1) comprises a preheating bin (11) for preheating the material to be dried, wherein the preheating bin (11) is provided with a feed inlet, and the feed inlet is connected to a discharge port of a storage bin (7) for the material to be dried; A microwave drying and cracking mechanism (2) is used to perform microwave drying and cracking on the preheated material, comprising a microwave drying and cracking box (21) and at least one microwave device fixedly arranged on the microwave drying and cracking box (21), wherein the feed inlet of the microwave drying and cracking box (21) is connected to the discharge outlet of the preheating chamber (11) via a connecting pipe (3); Negative pressure mechanism (4): used for evacuating the preheating chamber (11) and the microwave drying and cracking box (21) to obtain a negative pressure environment, and the negative pressure mechanism (4) is connected to the preheating mechanism (1).

2. The vacuum microwave drying cracking device according to claim 1, characterized in that: A first double-screw feeder (12) is fixedly arranged in the preheating bin (11), and a first motor (13) for driving the first double-screw feeder (12) to move is arranged on the preheating bin (11).

3. The vacuum microwave drying cracking device according to claim 1, characterized in that: A second double-screw feeder (23) is fixedly arranged in the microwave drying and cracking box (21), and a second motor (24) for driving the second double-screw feeder (23) to move is arranged on the microwave drying and cracking box (21).

4. The vacuum microwave drying cracking device according to claim 1, characterized in that: The negative pressure mechanism (4) comprises a vacuum pump (41), a vacuum tank (42) and a water storage tank (43); the vacuum pump (41) is connected to the vacuum tank (42) via a vacuum pipeline; the vacuum tank (42) is connected to the water storage tank (43); and the vacuum tank (42) is in communication with the preheating chamber (11).

5. The vacuum microwave drying and cracking device according to claim 1, characterized in that: The microwave device is a radiation type microwave heater (22), and the radiation type microwave heater (22) is fixedly arranged on the top cover plate of the microwave drying and cracking box (21).

6. The vacuum microwave drying and cracking device according to claim 1, characterized in that: The connecting pipe (3) is made of stainless steel, and a foam insulation layer is fixedly provided on the side wall of the connecting pipe (3).

7. The vacuum microwave drying and cracking device according to claim 1, characterized in that: The inner wall of the microwave drying and cracking box (21) is provided with a wave-absorbing composite material layer and a non-wave-absorbing heat-insulating layer in sequence from the inside to the outside.

8. The vacuum microwave drying and cracking device according to claim 1, characterized in that: The microwave drying and cracking box (21) is provided with a humidity detection device (5) and a temperature and pressure detection device (6).

9. The vacuum microwave drying and cracking device according to claim 1, characterized in that: The bottom of the microwave drying and cracking box (21) is connected to a material pouring valve (8).

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